AltOR32 is an alternative OpenRISC 1000 architecture derived RISC CPU which only implements the essential OpenRISC instructions and is targeted at smaller FPGAs.
This core makes use of the stock OpenRISC GCC port, but omits the vector, floating-point, 64-bit extensions & hardware multipliers / division.
AltOR32 easily fits on the Papilio One 250K (XC3S250E), and comes in pipelined & multi-cycle versions.
The Papilio One 250K port contains a Bootloader (with SPI PROM programmer), UART, Timers & GPIO and can run at over 40MHz.
The source, example FPGA project & bit files are available at OpenCores